Venus Not An Ideal Vacation Spot
Venus! I am not thinking of the goddess of love here. I am about to celebrate my 50th wedding anniversary this coming June and I secretly think I married the goddess of love, but I want to write here about the planet Venus, the second planet from the Sun.
Some of my readers have lately asked me what that bright light in the west is that they can see after sunset. It is the planet Venus, our so-called “Sister Planet.” It is called this because it is about the same size as Earth and closer to us than Mars, which is outside the Earth’s orbit. When Venus is seen after sunset, it is sometimes called the “Evening Star” and when it is seen before sunrise, it has been called the “Morning Star.”
Venus has always been something of a mystery planet. Even into the 20th century, some astronomers wondered if, hidden below dense clouds as it always is, there might be an Earthlike surface or even a dense jungle of primordial vegetation. It wasn’t until humans could put a lander on the surface of Venus, carrying some basic instruments, that we could understand that the surface of Venus is anything but Earth-like! The Soviets were the first to put a lander on Venus and Americans have since taken high-resolution radar images of the surface. We have a good map of the surface terrain of Venus and a good idea of what conditions are like on the surface.
Some science fiction writers have speculated that Venus might be a sort of resort, a nice place to take a vacation.
It is a terrible place! While Earth lies about 93 million miles from the Sun, Venus lies 67.7 million miles from the Sun. This means the solar radiation that falls on Venus is much more intense than it is on Earth. This greatly increases surface temperature. The average surface temperature of Venus is 864 degrees Fahrenheit! The melting point of lead is 872 degrees Fahrenheit and sometimes Venus can be that hot! Not a good vacation spot…
In addition, the atmosphere is much heavier, more than 100 times that of Earth. The atmosphere is composed of hot carbon dioxide and vaporous sulfuric acid droplets. It exerts a pressure equivalent to the pressure of 3,000 feet of water. So…imagine you land on Venus in just jeans, a short-sleeved shirt or blouse, with flip-flops on your feet. In just seconds, you would be smashed into a puddle which would soon be roasted to smoke!
Why is Venus as it is? It is because of the Sun’s radiation on Venus. Planetologists speculate that Venus probably started out about like Earth. It had some carbon dioxide joined in calcium carbonate [limestone] in its surface rocks, just as Earth did. However, when Venus’ limestone was super-heated by the Sun, it released this Carbon Dioxide to any surrounding atmosphere that existed. Soon, it became the atmosphere.
Carbon dioxide is a “greenhouse gas.” That is, when solar radiation strikes Venus, the generated heat is trapped below Venus’ atmosphere and it cannot escape much as heat is trapped under the glass of a greenhouse. On Earth, we re-radiate much of the solar heat we accumulate each day back into space each night and the Sun’s heat does not accumulate in a “runaway greenhouse effect” as it does on Venus. Earth’s atmosphere is mostly nitrogen and oxygen—with some carbon dioxide. Most scientists are concerned about the amount of carbon dioxide we release into our atmosphere because this could contribute to a greenhouse effect and hence to global warming.
Galileo was the first to notice that Venus has phases, as our Moon does. I have included an image of Venus which I made in April as a joint effort between myself and my great friend and fellow sky-watcher, Dr. Clinton Willis. Planetary photography is very difficult. It took a team effort to get the image of Venus we got. It does show Venus’ phase in late April. As May comes on, Venus will become more and more a thinning crescent. I hope to photograph it again as a very thin crescent towards the end of May.
May will still be the season for viewing galaxies and Mars, Saturn and Jupiter can be seen before dawn in the southeast.
Clear skies to all!